Kenneth B. Wiberg, a pioneering physical-organic chemist who served as professor of chemistry from 1962 to 1998, died on May 10.
‘True giant in organic chemistry’: Yale’s Kenneth B. Wiberg dies at 98
Kenneth B. Wiberg
Kenneth B. Wiberg, a pioneering chemist whose research illuminated the nature of the chemical bond and who served as chair of the Department of Chemistry from 1968 to 1971, died in Needham, Massachusetts, on May 10 at the age of 98.
Wiberg, the Eugene Higgins Professor Emeritus of Chemistry at Yale, served on the University of Washington faculty before coming to Yale in 1962. As a Yale chemistry professor, he taught organic chemistry and conducted seminal research in physical organic chemistry.
His many contributions to chemistry and the department are marked by his passion for research, dedication to teaching, and enthusiasm for staying ahead of the curve. As a result, he had a pronounced influence on the department’s positive reputation and development.
Ken was a true giant in organic chemistry and will be remembered as a key figure in the history of Yale Chemistry.”
Chemistry Department Chair Nilay Hazari
When Wiberg came to Yale at the invitation of then-Chair Harry Wasserman, the Department of Chemistry became the world’s leading center for physical-organic chemistry.
Chemistry professor emeritus J. Michael McBride said this about Wiberg’s research in a 1997 article:
Poster for a symposium honoring Wiberg
“Professor Wiberg’s impact on the field of physical-organic chemistry includes playing a key role in applying molecular-orbital computational methods towards the understanding of bonding, reactivity, and spectral properties of organic molecules.”
“Professor Wiberg’s research has brought a wide range of new techniques to bear on questions concerning the structure and reactivity of organic molecules. His synthetic, spectroscopic and mechanistic studies of highly strained small-ring compounds have helped illuminate the nature of the chemical bond.” Professor Wiberg’s research extended “to studies of solvent effects on chemical processes and of the physical origin of NMR chemical shifts.”
Early in his career, Wiberg did landmark work on the mechanism of oxidation reactions and chirality. He also became known for the wide range of physical and computational techniques that he skillfully brought to bear on determining the properties of carbon-carbon bonds, especially when strained by inclusion in small-ring polycyclic compounds.
Not only did he succeed in preparing compounds that many organic chemists thought incapable of existence, but he also examined their spectroscopic and thermodynamic properties, and used these results to test and improve burgeoning computational methods.
His early study of small rings focused on cyclopropane, a three-membered carbon ring that was thermally converted into propene. He collaborated with physical chemists to study this conversion. Subsequently, he developed procedures to prepare both cis and trans 1,2-dideuterium labeled derivatives. The thermolysis led to both cis-trans conversion and propene formation, showing that the initial process was cleavage of the C-C bond to form a diradical.
Later, having made bicyclobutane, Wiberg attempted what others thought impossible: to add another three-membered ring to give propellane. To examine the possible stability of this compound, he needed a computer to carry out ab initio calculations for propellane and several possible mechanisms for its dissociation. Wiberg secured the department’s first computer and went on to prove the requisite stability. This led to its synthesis.
Several years later, chemist Phil Baran of The Scripps Research Institute made use of its strain energy in making numerous complex molecules. What started as chemical curiosity for Wiberg resulted in hundreds of papers incorporating his work, not to mention the introduction of computational chemistry to the department.
In a 2023 article, Wiberg humbly summarized his work. “My lab made strange compounds and [performed] calculations of their properties.”
Kenneth B. Wiberg
But more than that, he and other professors trained the next generation of leaders in physical-organic chemistry while simultaneously bridging subdisciplines and promoting collaboration across the department—a hallmark that still exists to this day.
“There are two kinds of departments. Some are very divisionally head-up; the organic chemists talk with the organic chemists; the inorganic chemists talk with the inorganic chemists. Yale was very different,” he said in the 2023 article. “I did collaborative work with several of my colleagues. And it was a very pleasant place to work. I enjoyed going to work there.”
Scott Miller, Sterling Professor of Chemistry at Yale, had this to say:
“Ken Wiberg was not only inspirational for his scientific accomplishments, but also for his curiosity, open mind, and humanity. In so many ways, Ken was at the role model level when it came to illustrating what it means to be a professor.”
His secretary of 15 years, Jen Liner, said, “He cared about his students and gave them advice and direction toward their goals. He was direct and honest in a very compassionate way. I will always remember Dr. Wiberg as very kind and understanding, and a wonderful professor.”
One graduate student from Wiberg’s research group recalls presenting their results and course of action at weekly meetings. Wiberg offered suggestions so subtly that students thought the plans were theirs. In reality, he was gently steering the research direction.
A member of Wiberg’s research group, Mark Murcko ’89 Ph.D., said:
“I joined Ken’s group because there was so much going on—a diverse and exciting mix of synthesis, calorimetry, spectroscopy, and computation—all in the service of increasing our understanding of the fundamental properties of organic molecules. Ken would set the broad research directions, then give us the freedom to explore; he let us figure things out for ourselves and make our own mistakes along the way, while always being available to offer gentle advice and guidance. We became scientists under his wing.”
Wiberg’s love of chemistry started at a young age, when he and an elementary school friend performed experiments from a chemistry set. He went on to complete a three-year chemistry program at Brooklyn Technical High School before earning a bachelor’s degree at the Massachusetts Institute of Technology in 1948. He earned his Ph.D. in organic chemistry in 1950 from Columbia University, where he studied reaction mechanisms using stereochemistry alongside Professor William Doering.
Wiberg published over 470 papers.
Wiberg with wife Marge and colleagues Harry Wasserman and Peter Moore at his 60th birthday celebration at Yale (Image courtesy of Paul Okarma)
He was a member of the National Academy of Sciences and the American Association of Arts and Sciences, and a fellow of the American Academy of Arts and Sciences. He has won the Arthur C. Cope Award for his achievements in the field of organic chemistry research, the American Chemical Society Award in Physical-Organic Chemistry, and the Pauling Award.
In retirement, he wrote his memoir, published several papers on computational studies, traveled, and lectured on chemistry to his community of friends.
Wiberg, who lived in Massachusetts, was predeceased by his wife Marge. He is survived by three children and five grandchildren.
A private funeral service was held for Ken. Flowers can be sent to the family or a tree planted in his memory by visiting the funeral home’s floral store.